1. Field of the Invention
The present invention relates to an original feeding device adapted to be fitted on an overhead projector.
2. Related Background Art
In the known overhead projector, the user who is making a presentation has to manually place the transparency sheets, or the originals for such overhead projector, one by one on the display stage of the overhead projector, and such sheet replacing operation has been an obstacle to the presentation. Also, the already projected sheets and those to be projected are often mixed up on the table, and such situation has also been an obstacle to the presentation.
Such drawbacks will be resolved by a device for automatically feeding the sheets onto the display stage of the overhead projector (OHP), but such device has not been realized because of the following difficulties.
In such an OHP original feeder for feeding the OHP originals, the center of the display stage should preferably coincide with that of the original to be displayed in order to facilitate observation of the observers, but such requirement cannot be met if the originals are variable in size or if vertically oblong originals and laterally oblong originals are mixedly present.
On the other hand, in the OHP original feeder for feeding the OHP originals by means of a conveying film, such convey film represents a considerable portion of the cost. For this reason, the gaps between the originals are generally shortened in order to economize the amount of the convey film to be used. However, if the gaps are made too short, there will result a drawback that, while an original is projected on the display stage, the next original is partly projected.
Also, in such an OHP original feeder for feeding the OHP originals by means of the convey film, if a user cuts off the power supply while erroneously leaving his OHP originals on the feeder and if the next user tries to feed his originals without noticing such left originals, the original feeding becomes impossible because of the limit in the number of originals receivable in the feeder.
Also, in the OHP original feeder for feeding the OHP originals, the user often wishes to make fine adjustment on the stopping position of the OHP original on the display stage.
Furthermore, in the OHP original feeder for feeding the OHP originals, the observer receives an unpleasant impression if the original feeding is too fast, as the feeding is effected while the original is projected. However, if the original feeding is too slow, there will be required an excessively long time, interfering with the limited time of presentation.